Re: Problem with long range data???
I gotta tell ya Frank - your last post to me is like opening up "Zen and the Art of Motorcycle Maintenance" to a random page somewhere over half way through the book and just starting reading. Letters clustered into words, words clustered into sentences, sentences into paragraphs - but I am not really sure what you are trying to say.
You see, I'm just a dumb techie-oriented guy. I like to work with a few well known pieces of information, when a few well known pieces of information will support me accomplishing my goals. I also seek out and leverage the work of folks a whole lot smarter than me whenever possible. With that in mind, let's back way up here to a few basic points, at least from the "world of Leo" perspective:
- The purpose of a chronograph is two fold; one, to determine the MV of a given rifle/load combination so that value can be used as ONE OF MANY initial inputs into a ballistic program so that an initial trajectory and wind table can be produced. Two, the chrono is an aid in load development. In that role, the first thing it is used for is to determine when you have achieved your Target Velocity for a given bullet weight/barrel length combo. Target velocity, when working with known components, tells you that a) you are in a range of velocity where you can expect consistent results from the load, and b) that the load will work within the temperature range you would expect in the use of the weapons system. The second thing it is for is to determine your ES and SD, as these are essential values for long range shooting. ES and SD reflect both the quality of your reloading process as well as where you are on the pressure curve for a given powder. When target velocity, low ES/SD, and the use of known components and loading practices line up, you have your "load".
Note that the two uses above are backwards; the MV that will be used for the first purpose is an outcome of the second purpose. In the case of ammo you must use from a source other than your own reloading, the data from both purposes are of value to the shooter.
Once this information is extracted, the chrono has done its job. In that role, do I want said chrono to be accurate and convenient? Damn skippy I do. If that is a "Litz Fallback", well then I'm happy to stand up and proclaim myself a "Litz "Fallbacker".
Now that the chrono has done its job and is back in its box, we have another step in front of us - Calibrating our WS (rifle, scope, and ammo) to a mathematical predictor of our bullet's a) trajectory, and b) wind drift. For practical purposes, we can discard the notion of calibrating for wind drift. Reality dictates that we will not be able to gather sufficient instrumented data in a controlled environment to do better than the mathematical predictor, so ignore this one. That leaves us with trajectory.
Any disagreement so far? I suspect not.
Now, on to the task of calibrating the WS and mathematical trajectory predictor. So, what are we really doing in this step? Multiple things actually. One of them is calibrating the predictor to OUR REAL SIGHT CLICK VALUES. Huhh... agreed, right? Time for me to exercise my right to be a "Litz "Fallbacker" again. Starting on page 131 of his book, he goes into a nice explanation of this for those that might need education on the subject and fortification of its importance. Now, given your background and extensive experience with scopes from multiple providers, that point is well engrained in your mind. However, not a day goes by on your web site where this point is lost on multiple posters.
OK, now more on the mathematical trajectory predictor. Well, seein's that I am from Indiana and fell off the back of my share of turnip wagons in my younger days, it is quite astonishing that I can still stare at the G1 Standard Projectile, the G7 Standard Projectile, some of the bullets I plan to send down range, and discern that 2 of the 3 look a whole lot a like while one looks like canine excrement in comparison to the other two. Astonishing that I can, but true.
So, here you got this dumb Hoosier-fell-off-the-back-of-the-turnip-wagon-one-too-many-times guy that likes shooting rifles, and he stumbles across all this data derived using a projectile that no longer looks like canine excrement; my lack of gumption, original thought, and low IQ has me clammerin' to that G7 thingamabob like stink on canine... well, let's just leave it at clammering Frank... again, I admit it - I deserve the label of "Litz "Fallbacker" due to my fondness of the G7 Standard Projectile. Sniff.
OK OK, back to the task at hand - calibrating our mathematical trajectory predictor to our WS in a fashion that generates us some usable, predictable data. Only one way I know of for me start the next step - drive my dumb Hoosier-fell-off-the-back-of-the-turnip-wagon-one-too-many-times ass to the nearest KD range armed with some weather instrumentation devices and start shootin'!!! The initial trajectory table will most likely keep me from givin' my poor buddy that drew the short straw and has the first turn in the pits a dirt shower, so really that was the only reason we printed the danged thing out before we loaded our dumb Hoosier-fell-off-the-back-of-the-turnip-wagon-one-too-many-times ass in the truck to leave for the range in the first place.
Now, I will tell you that I have not invested a lot of time in evaluating ballistic programs, one versus t'uther, as I only shoot out to 1000 yards in field sit-e-ations. I have followed the Michael Field method (see previous references to lack of gumption and original thought), where once you have tweaked JBM to give you a matching trajectory curve to match your actual data at a given air density you can change the density and the curve will give you a pretty good chance of hitting what you are aiming at elevation-wise. I also use the - uh oh, here I go again - WARNING - Brace yourself for another ""Litz "Fallbacker" moment - ballistics program Bryan provided with his first addition book.
So there you go Frank. All out in the open, ready for critique. Here to learn primarily, entertain secondarily.
